diff --git a/tool/prepare-port/setup.sh b/tool/prepare-port/setup.sh
index b055e826b..e12081051 100644
--- a/tool/prepare-port/setup.sh
+++ b/tool/prepare-port/setup.sh
@@ -1000,11 +1000,11 @@ checkPhase() {
 installPhase() {
     runHook preInstall
 
-    if [ -n "$prefix" ]; then
-        mkdir -p "$prefix"
+    if [ -n "$source" ]; then
+        mkdir -p "$source"
     fi
 
-    cp -r ./* "$prefix"
+    cp -r ./* "$source"
 
     runHook postInstall
 }